Fix last line text alignment when using padding insets

[inickt]

Summary

Fixes #470. In addition to center, it turns out right alignment was also broken when some padding insets were set.

The solution was more straightforward than I thought. I passed in the paddingInsets so we could correctly determine how to align the last line relative to the superlayer. Since the left and right padding could be different, we couldn't derive this from the existing properties.

I simplified the math I originally used to figure out the right and center alignment values. If it is still confusing, I'd be happy to split the calculations over a couple lines and annotate with comments.

I tested by modifying the demo app. I am not too familiar with the project and whether this could be something easily unit tested.

Screenshots

Right Alignment

| Parameters | Before | After | | --- | --- | --- | | Left Padding: 0
Right Padding: 0
Percent: 50 | | | | Left Padding: 100
Right Padding: 100
Percent: 50 | | | | Left Padding: 100
Right Padding: 0
Percent: 50 | | | | Left Padding: 0
Right Padding: 100
Percent: 50 | | | | Left Padding: 50
Right Padding: 100
Percent: 100 | | |

Center Alignment

| Parameters | Before | After | | --- | --- | --- | | Left Padding: 0
Right Padding: 0
Percent: 50 | | | | Left Padding: 100
Right Padding: 100
Percent: 50 | | | | Left Padding: 0
Right Padding: 0
Percent: 100 | | | | Left Padding: 100
Right Padding: 0
Percent: 100 | | | | Left Padding: 0
Right Padding: 100
Percent: 100 | | | | Left Padding: 50
Right Padding: 100
Percent: 100 | | | | Left Padding: 100
Right Padding: 100
Percent: 100 | | |

Requirements

• [x] I've read and understood the Contributing guidelines and have done my best effort to follow them.
• [x] I've read and agree to the Code of Conduct.

[inickt]

Thanks for maintaining such a great project!